|Locale||Tamil Nadu, Kerala and Karnataka|
|Operator(s)||Southern Railway, South Western Railway|
|Rolling stock||WDM-2, WDM-3A, WDM-3D, WDG-3A and WDG-4 diesel locos; and WAG-7 and WAP-4 electric locos.|
|Track length||Main line: 390 km (242 mi)
Salem-Yeshvantapur 229 km (142 mi)
Salem-Mettur Dam 39 km (24 mi)
Irugur-Coimbatore-Mettupalayem 54 km (34 mi)
|Track gauge||1,676 mm (5 ft 6 in) broad gauge|
|Operating speed||Up to 130 km/h|
|Highest elevation||Jolarpettai 405 metres (1,329 ft)
Coimbatore 411 metres (1,348 ft)
Yeshvantapur 919 metres (3,015 ft)
The Jolarpettai–Shoranur line connects Jolarpettai, on the Chennai Central-Bangalore City line in the Indian state of Tamil Nadu and Shoranur in Kerala. There are several branch lines: Salem-Dharmapuri-Hosur-Yeshvantapur, Salem-Mettur Dam and Irugur/Podanur-Coimbatore-Mettupalayem connecting to Udhagamandalam (Ooty) via Nilgiri Mountain Railway. This network links the railway network in Kerala to the networks in Tamil Nadu and Karnataka, and subsequently other states.
The first train service in southern India and the third in India was operated by Madras Railway from Royapuram / Veyasarapady to Wallajah Road (Arcot) in 1856. Madras Railway extended its trunk route to Beypur / Kadalundi (near Calicut) in 1861
The Podanur-Mettuapalayam line was opened to traffic in 1873. The UNESCO heritage track, Nilgiri Mountain Railway was opened in two stages. The Mettupalayam-Coonoor section was opened in 1899 and it was extended up to Udhagamandalam (Ooty) in 1908. The 46 km (29 mi) long railway rises from 330 metres (1,080 ft) at Mettuapalaym to 2,200 metres (7,200 ft) at Udhagamandalam.
Two 762 mm (2 ft 6 in) wide narrow gauge famine protective lines were opened in the early years of the twentieth century. The 25.25 mi (41 km) long Tirupattur-Krishnagiri line was opened in 1905 and the 18.5 mi (30 km) long Morappur-Dharmapuri line was opened in 1906 and extended to Hosur - 54.5 mi (88 km) long . The Hosur-Dharmapuri line was decommissioned in 1941 and other two lines were closed around 1945.
The mainline was electrified in stages. The Jolarapettai-Morapur sector was electrified in 1989-90, the Morapur-Salem (excluded) in 1990-91, the Salem-Erode sector in 1991-92, the Tripur-Waylar sector including Coimbatore in 1995-96, and the Waylar-Vallatolnagar (beyond Shoranur, towards Ernakulam) in 1996-97. The Magnesite-Mettur Dam sector was electrified in 1990-91.
As of 2013, electrification of Coimbatore-Mettuapalayem is to be taken up this fiscal.
The Arakkonam-Jolarpettai-Salem-Erode-Coimbatore-Ernakulam line is classified as a "Group B" line which can take speeds up to 130 km/h.
Erode diesel loco shed holds WDM-2, WDM-3A, WDM-3D, WDG-3A and WDG-4 locos. Erode loco shed holds WAG-7 and WAP-4 locos. It is home to the largest fleet of WAP-4 locos on Indian Railways and handles some of the longest routes for electric trains in the country.
Jolarpettai has an electric/ diesel trip shed.
In the early 1950s legislation was passed authorizing the central government to take over independent railway systems that were there. On 14 April 1951 the Madras and Southern Mahratta Railway, the South Indian Railway Company and Mysore State Railway were merged to form Southern Railway. Subsequently, Nizam's Guaranteed State Railway was also merged into Southern Railway. On 2 October 1966, the Secunderabad, Solapur, Hubli and Vijayawada Divisions, covering the former territories of Nizam's Guaranteed State Railway and certain portions of Madras and Southern Mahratta Railway were separated from Southern Railway to form the South Central Railway. In 1977, Guntakal division of Southern Railway was transferred to South Central Railway and the Solapur division transferred to Central Railway. Amongst the seven new zones created in 2010 was South Western Railway, which was carved out of Southern Railway.
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